Remove <input>._parsedValue

It is not a concept in the spec, and the call sites were awkward with it
anyway.

lib/jsdom/living/nodes/HTMLInputElement-impl.js

@@ -478,8 +478,8 @@ class HTMLInputElementImpl extends HTMLElementImpl {
       return NaN;
     }
 
-    const parsedValue = this._parsedValue;
-    return typeof parsedValue === "number" ? parsedValue : NaN;
+    const parsedValue = this._convertStringToNumber(this._value);
+    return parsedValue !== null ? parsedValue : NaN;
   }
 
   set valueAsNumber(v) {
@@ -566,7 +566,7 @@ class HTMLInputElementImpl extends HTMLElementImpl {
       return;
     }
 
-    this.valueAsNumber = value;
+    this._value = this._convertNumberToString(value);
   }
 
   stepDown(n = 1) {
@@ -833,23 +833,12 @@ class HTMLInputElementImpl extends HTMLElementImpl {
     return null;
   }
 
-  get _parsedValue() {
-    if (this._convertStringToNumber !== undefined) {
-      return this._convertStringToNumber(this._value);
-    }
-    return this._value;
-  }
-
-  get _parsedValueIsNumber() {
-    if (this._convertStringToNumber === undefined) {
-      return false;
-    }
-    return typeof this._parsedValue === "number";
-  }
-
   // https://html.spec.whatwg.org/multipage/input.html#concept-input-step
   get _allowedValueStep() {
-    const attr = this._getAttributeIfApplies("step");
+    if (!this._contentAttributeApplies("step")) {
+      return null;
+    }
+    const attr = this.getAttributeNS(null, "step");
     if (attr === null) {
       return this._defaultStep * this._stepScaleFactor;
     }
@@ -972,7 +961,8 @@ class HTMLInputElementImpl extends HTMLElementImpl {
       // than the minimum, the element is simultaneously suffering from an underflow and suffering
       // from an overflow.
       const reversedRangeSufferingOverUnderflow = () => {
-        return this._parsedValueIsNumber && this._parsedValue > this._maximum && this._parsedValue < this._minimum;
+        const parsedValue = this._convertStringToNumber(this._value);
+        return parsedValue !== null && parsedValue > this._maximum && parsedValue < this._minimum;
       };
 
       const state = {
@@ -1041,8 +1031,11 @@ class HTMLInputElementImpl extends HTMLElementImpl {
           // range, and the result of applying the algorithm to convert a string to a number to the
           // string given by the element's value is a number, and the number obtained from that
           // algorithm is more than the maximum, the element is suffering from an overflow.
-          if (this._maximum !== null && this._parsedValueIsNumber && this._parsedValue > this._maximum) {
-            return true;
+          if (this._maximum !== null) {
+            const parsedValue = this._convertStringToNumber(this._value);
+            if (parsedValue !== null && parsedValue > this._maximum) {
+              return true;
+            }
           }
           return false;
         },
@@ -1057,8 +1050,11 @@ class HTMLInputElementImpl extends HTMLElementImpl {
           // range, and the result of applying the algorithm to convert a string to a number to the
           // string given by the element's value is a number, and the number obtained from that
           // algorithm is less than the minimum, the element is suffering from an underflow.
-          if (this._minimum !== null && this._parsedValueIsNumber && this._parsedValue < this._minimum) {
-            return true;
+          if (this._minimum !== null) {
+            const parsedValue = this._convertStringToNumber(this._value);
+            if (parsedValue !== null && parsedValue < this._minimum) {
+              return true;
+            }
           }
           return false;
         },
@@ -1093,12 +1089,8 @@ class HTMLInputElementImpl extends HTMLElementImpl {
           if (allowedValueStep === null) {
             return false;
           }
-          if (!this._parsedValueIsNumber) {
-            return false;
-          }
-
-          const number = this._parsedValue;
-          return !this._isStepAligned(number);
+          const number = this._convertStringToNumber(this._value);
+          return number !== null && !this._isStepAligned(number);
         },
 
         // https://html.spec.whatwg.org/multipage/form-control-infrastructure.html#suffering-from-a-type-mismatch